Vosmaeropsis complanatispinifera, Cavalcanti, Fernanda F., Bastos, Nilma & Lanna, Emilio, 2015

Cavalcanti, Fernanda F., Bastos, Nilma & Lanna, Emilio, 2015, Two new species of the genus Vosmaeropsis Dendy, 1892 (Porifera, Calcarea), with comments on the distribution of V. sericata (Ridley, 1881) along the Southwestern Atlantic Ocean, Zootaxa 3956 (4), pp. 476-490 : 481-487

Vosmaeropsis complanatispinifera sp. nov.

Synonymies: Vosmaeropsis sericatum: Borojevic & Peixinho, 1976: 1015 , Fig. 17 (not Ridley, 1881: 134, plate XI, Fig. 5 ).

Etymology. complanatispinifera = due to the flattened (Lat. complanatus) apical actine that bears spines (Lat. spina).

Diagnosis. Vosmaeropsis with a tubular shape and leuconoid aquiferous system. The sponge surface is very hispid due to the presence of several large diactines, which have sharp or arrow-shaped distal tips. The choanosomal skeleton is composed mainly of triactines, but rare tetractines may be present. The atrial skeleton is formed mainly by tetractines, in which the apical actine is flattened and has spines, and also by few triactines.

Type material. UFBA 1882-POR [Holotype. Off Touros, 04°41’S – 35°24’05’’W, Rio Grande do Norte state, Brazil; depth: 65 m; 17/X/1967; SAL 1677], UFBA 36-POR [Paratype. Alagoas state, 09°01’07’’S – 35°06’05’’W, Brazil; depth: 36 m; 10/IX/1965; AKA 8], UFBA 85-POR [Paratype. Rio Grande do Norte state, 03°28’S – 35°06’05’W, Brazil; depth: 61 m; 17/X/1967; SAL 1682]. All the specimens were collected by M. Kempf.

Type locality. Rio Grande do Norte state, Brazil.

Additional analysed material: UFBA 19-POR [Off Piaçabuçu, 10°26’03’’S – 36°03’03’’W, Alagoas state, Brazil; depth: 40 m; 03/IX/1965; AKA 95], UFBA 29-POR [Off Maceió, 09°41’04’’S – 35°28’02’’W, Alagoas state, Brazil; depth: 36 m; 07/IX/1965; AKA 53], UFBA 31-POR [Off Maragogi, 09°01’05’’S – 35°01’03’’W, Alagoas state, Brazil; depth: 36 m; 10/IX/1965; AKA 7], UFBA 58-POR [Recife, 08°11’00’’S – 34°45’03’’W, Pernambuco state, Brazil; depth: 30.5 m; II/1966 – V/1967; REC 122], UFBA 66-POR [Recife, 08°16’02’’S – 34°51’07’’W, Pernambuco state, Brazil; depth: 25.5m; II/1966 – V/1967; REC 111], UFBA 68-POR [Recife, 08°09’09’’S – 34°45’08’’W, Pernambuco state, Brazil; depth: 27 m; II/1966 – V/1967; REC 4], UFBA 72-POR [08°01’05’’S – 34°39’03’’W, Pernambuco state, Brazil; depth: 28 m; II/1966 – V/1967; REC 150], UFBA 126-POR [Off Abrolhos, 17°55’S – 37°30’W, Bahia state, Brazil; depth: 47 m; 17/IX/1968; SAL 1966], UFBA 1876-POR [Fernando de Noronha Archipelago, 03°50’08’’S – 32°27’05’’W, Pernambuco state, Brazil; depth: 55 m; 10/X/ 1967; SAL 1667b], and UFBA 1881-POR [Fernando de Noronha Archipelago, 03°50’07’’S – 32°28’01’’W, Pernambuco state, Brazil; depth: 65 m; 10/X/1967; SAL 1667a]. All the specimens were collected by M. Kempf.

Description: Colour of the preserved specimens is beige to light brown. Most of the specimens are fragmented, but it is possible to recognise that they had a tubular shape ( Figure 5 A). A single osculum, ornamented by a fringe of trichoxea, is present at the top of the sponges; the single exception is the specimen UFBA 19 - POR that has three oscula. The sponge surface is very hispid due to the presence of several large diactines ( Figures 5 A, C). The atrial cavity is wide. It is pierced by the proximal tips of some diactines that cross the sponge wall, and also by the apical actine of the atrial tetractines ( Figures 5 C, D). The aquiferous system is leuconoid and most of the choanocyte chambers are elongated or spherical ( Figure 5 E). Some of them seem to be branched, possibly due to artifacts of the fixation and/or preservation of the specimens.

The cortical skeleton is composed of tangential triactines disposed in several layers ( Figure 5 B). The subcortical skeleton is formed by a layer of pseudosagittal triactines that are positioned with their longest paired actines pointed inwards ( Figure 5 F). One category of triactines is present at the choanosomal skeleton. These spicules point their unpaired actine towards the cortex, which together with the longest actine of the pseudosagittal triactines makes an inarticulated skeleton. In the paratypes ( UFBA 36 - POR and UFBA 85 - POR), we also observed rare choanosomal tetractines. The atrial skeleton is formed mainly by small tetractines, which project their apical actine into the atrial cavity, making it hispid. Additionally, few atrial triactines were also observed. Fragments of trichoxea are present at the cortical and atrial skeletons ( Figure 5 G), being tangentially positioned.

Spicules ( Table 2): Trichoxeas ( Figure 5 G): Hair-like spicules, usually broken, measuring at least 250 µm.

Diactines ( Figure 6 A): Variable in size and slightly curved. The proximal tip is sharply pointed while the distal one is thick or arrow-shaped [588–1506.3 ± 211.3–2940/ 20– 60.5 ± 4.2–98 µm (n= 3 specimens)];

Cortical triactines ( Figure 6 B): Actines are cylindrical to slightly conical, with blunt tips. Paired actines are curved. Actines are equiradiated or (less frequently) the unpaired one is short [Paired actines: 120–251.6 ± 54.7– 392/ 10–19.2 ± 1.0–30 µm; unpaired actine: 100–219.3 ± 2.5–333/ 10–19.8 ± 1.9–30µm (n= 3 specimens)];

Subcortical triactines ( Figure 6 C): Pseudosagittal. Actines are conical, with blunt tips. Unpaired actine can reach the same size of the shortest paired actine [Paired actine I: 100–257.3 ± 21.5–450/ 10–20.4 ± 1.0–30 µm; paired actine II: 210–365.2 ± 31.4–590/ 10–20.6 ± 0.8–35 µm; unpaired actine: 100–177.6 ± 15.7–330/ 10–21.0 ± 1.0–30 µm (n= 3 specimens)];

Choanosomal triactines ( Figure 6 D): They are large. Actines are conical, and with blunt tips. In general, the unpaired actine is longer than the paired ones [Paired actines: 250–362.3 ± 43.0–490/ 20 –28.0 ± 4.9–40 µm; unpaired actine: 300–510.9 ± 52.1–720/ 20–29.6 ± 4.0–40 µm (n= 3 specimens)];

Choanosomal tetractines ( Figure 6 E): Rare and similar to the choanosomal triactine. The apical actine is short and very thin [Paired actines: 190–308.8 ± 48.8–400/ 20– 25.2 ± 2.7–30 µm; unpaired actine: 350–436.4 ± 61.6– 570/ 20–28.6 ± 2.0–30 µm; apical actine: 20–40.0 ± 14.1–70/ 10–12.3 ± 0.8–20 µm (n= 2 specimens)];

Atrial tetractines ( Figures 6 F; 7): Actines are cylindrical and with sharp tips. In general, the basal actines are regular, but sometimes the paired actines are curved and/or longer than the unpaired one. The apical actine is shorter than the basal ones and have a very peculiar shape: it is flattened (like a knife) and ornamented with small spines [Paired actines: 130–270.4 ± 53.6–370/ 7–11.6 ± 2.8–15 µm; unpaired actine: 100–228.2 ± 67.4–370/ 10– 11.9 ± 2.5–15 µm; apical actine: 60–111.8 ± 3.7–190/ 10–12.6 ± 2.5–15 µm (n= 3 specimens)];

Atrial triactines ( Figure 6 G): Similar to the basal actines of the previous spicule category. They are not abundant [Paired actines: 130–234.7 ± 13.9–330/ 10–12.7 ± 2.4–20 µm; unpaired actines: 110–225.3 ± 6.1–370/ 10– 13.5 ± 3.4–25 µm (n= 3 specimens)]. Actines are cylindrical.

Spicule Actine Length (µm) Width (µm) N

Min. Mean SD Max. Mean SD

Diactines 588 1509.2 774.1 2587 63.7 34.9 0 6 Cortical triactines Paired 120 197.0 43.8 250 18.0 4.3 30 Unpaired 100 157.0 41.4 280 19.8 4.8 30 Subcortical triactines Paired 1 110 268.0 75.4 450 21.5 5.7 30 Paired 2 210 381.7 93.7 590 21.5 6.0 30 Unpaired 100 180.3 36.4 270 22.0 6.0 30 Choanosomal triactines Paired 250 391.7 66.2 490 33.5 6.4 30 Unpaired 360 557.7 111.5 720 34.2 5.4 30 Atrial triactines Paired 130 278.2 45.3 330 14.4 5.0 17 Unpaired 210 278.2 47.2 370 16.8 4.3 17 Atrial tetractines Paired 130 267.7 72.6 360 10.0 0.0 30 Unpaired 100 182.7 48.1 310 10.3 1.3 30 Apical 80 108.8 17.3 150 12.8 2.5 30 Ecology. According to Borojevic & Peixinho (1976), the specimens of V. complanatispinifera sp. nov. were found attached to calcareous algae ( UFBA 19-POR, UFBA 29-POR, UFBA 58-POR, UFBA 68-POR, UFBA 72- POR, UFBA 85-POR, UFBA 126-POR, UFBA 1876-POR, and UFBA 1881-POR), Halimeda sp., a green macroalgae ( UFBA 31-POR, UFBA 36-POR, and UFBA 66-POR), and a biogenic unidentified substrate ( UFBA 1882-POR).

Remarks. The specimens of V. complanatispinifera sp. nov. analysed here were formerly described as V. sericata by Borojevic & Peixinho (1976). Although the original description of V. sericata is very incomplete ( Ridley 1881), it is possible to recognise differences between this species and V. complanatispinifera sp. nov. The main difference is the composition of the atrial skeleton, which is formed exclusively by tetractines in V. sericata ( Ridley 1881) , but also by triactines in V. complanatispinifera sp. nov. The length of the apical actine of these atrial tetractines and of diactines is also different between them (Apical actines: 160–200 µm in V. sericata ; 60–190 µm in V. complanatispinifera sp. nov.; Diactines: 2000–3000 µm in V. sericata ; 588–2940 µm in V. complanatispinifera sp. nov.). Additionally, there are differences in the shape and size of their choanosomal triactines; according to Ridley (1881), in V. sericata the actines are almost equiradiated—the unpaired actine measures 355–520/ 19–32 µm while the paired ones are slightly smaller. In contrast, in V. complanatispinifera sp. nov. there is a clear difference between the length of the unpaired (300–510.9 ± 52.1–720 µm) and paired actines (250–362.3 ± 43.0–490 µm). Although we did not access the type specimen of V. sericata , we analysed photos taken from the slide BMNH 1879.12.27.15a (indicated as “ type ” and provided by C. Valentine and E. Sherlock by personal communication). Based on these photos, we observed that V. sericata has a greater abundance of diactines, and the tip of these spicules are not arrow-shaped. They are sharply pointed. In addition, there is a thick layer of atrial spicules in V. sericata , which is not seen in V. complanatispinifera sp. nov.

Only four of the previously known Vosmaeropsis species share with V. complanatispinifera sp. nov. the presence of large diactines and atrial tri- and tetractines ( V. cyathus , V. inflata , V. japonica , and V. g r i s e a) ( Table 3). Vosmaeropsis cyathus is a very different species due to the abundance and size of their diactines. Its surface is sparingly hispid due to the short projecting points of scattered diactines. Moreover, although Verril (1873) did not provide spicule measurements, he mentioned that these diactines are about as large as one of the actines of the cortical triactines. In V. complanatispinifera sp. nov., the sponge surface is very hispid due to the presence of abundant diactines, and these spicules are clearly larger than any other ( Figure 6 A, Table 2). Vosmaeropsis inflata has also a sparingly hispid surface, with spindle-shaped diactines that never protrude from the sponge surface. Finally, V. japonica , V. g r i s e a, and V. complanatispinifera sp. nov. can be distinguished mainly by the size of their subcortical spicules, as shown in Table 4.

Pseudosagittal triactines, Tetra. —Tetractines, Microdi—Microdiactines, Trich. —Trichoxea.

Species Corticalskeleton Subcortical Choanosomal skeleton Subatrial Atrial skeleton skeleton skeleton

Vosmaeropsis Di. (large and arrow-shaped) and Tri. Psag Tri. Tri. (large) and Tetra. (rare) - Tetra. (with spined apical

complanatispinifera sp. nov. actine) and Tri. (few)

. recruta sp. nov. Di. (large and arrow-shaped), Tri. and Trich. Psag Tri. Large Tri. and Tetra. (rare) Tri. (rare) Tri. and few Tetra.

(fragments)

. conexiva Poléjaeff, 1883 Tri. Psag Tri. Tri. Tri. Tri.

Species Paired I Paired II Unpaired

Length Width Length Width Length Width V. japonica 80–130 20–28 100–180 20–28 130–220 20–28 V. grisea 125–160 10–14 150–190 10–14 200–255 10–14 V. complanatispinifera sp. nov. 110–450 10–30 210–590 10–35 100–270 10–30 The two new species described here can be easily distinguished by their skeletal composition and spicule shape and size. The main difference can be attributed to the size of the large diactines: in V. recruta sp. nov. they measure 372–949.1 ± 59.7–2156/ 20–40.6 ± 2.7–78 µm, while in V. complanatispinifera sp. nov. they measure 588–1506.3 ± 211.3–2940/ 20–60.5 ± 4.2–98 µm. In addition, although both species have atrial tri- and tetractines, the most abundant spicule category in this region is different; in V. recruta sp. nov. there are mainly atrial triactines, while in V. complanatispinifera sp. nov. there are mainly atrial tetractines.

Finally, V. complanatispinifera sp. nov. is the first species described to Vosmaeropsis in which the apical actine of the atrial tetractines is flattened and with spines. It distinguishes V. complanatispinifera sp. nov. from all other known species of the genus, including the other new species described here.

Figures

FIGURE 5. Vosmaeropsis complanatispinifera sp. nov. (UFBA 1882 - POR, holotype). A—Fragments of the preserved specimen; B—Tangential section showing the cortical skeleton; C—Longitudinal section showing the cortex (cx) and atrium (at); D—Tangential section showing the atrial skeleton and apical actines with spines (arrowhead) penetrating the atrial cavity (in detail); E—Histological section showing spherical choanocyte chambers (cc); F—Longitudinal section showing the subcortical layer of pseudosagittal triactines (arrowheads); G—Detail of the fragments of trichoxea in the cortical skeleton (arrowheads).

FIGURE 6. Vosmaeropsis complanatispinifera sp. nov. (UFBA 1882 - POR, holotype). A—Diactine; B—Cortical triactine; C—Subcortical triactine; D—Choanosomal triactine; E—Choanosomal tetractine; F—Atrial tetractine; G—Atrial triactine.